Nick Herbert MP is right (All hail the Rubicops, 23 July) that "bad deals aren't a reason to turn our back on the private sector; they are a lesson to write contracts properly". However, neither is poor performance a reason to turn our back on the public sector; it is a lesson to manage performance in a expertly informed way (see Stephen Bolsin's piece on his work in Australia, 17 July).

But however good a contract with the private sector may be, five factors cannot be overcome. Private borrowing is more expensive than public borrowing, whether or not it is configured to keep it off the public borrowing balance sheet. "Proper contracts" involve many highly paid professionals, incurring costs that governments are shy to disclose. And once a contract has gone to the private sector, control is largely lost, as private firms can be taken over or bought out. A proportion of the money paid out by the state will go as profit to shareholders. And those highly paid professionals will find "tax-efficient regimes" at the expense of the exchequer (us).Marcus CleaverMalvern, Worcestershire

• Nick Herbert has discovered the holy grail of public service reform. Reduced spending equals improved performance and standards. Of course, the resource envelope is only one factor affecting the quality of public services. But a resource threshold is eventually reached. Early symptoms of stress points are already beginning to appear in relation to his principal example of reform, policing, something dear to his heart while a justice minister. It will be a while before this shows up in crime outcomes, which in any case have been on a downward trajectory since the mid-1990s.

In the example of healthcare, the increased investment under Labour had a demonstrably positive impact on outcomes, reflected in dramatically reduced waiting times and increased patient satisfaction.

Of course, for politicians of his persuasion, there can never be too much of what he calls "independent" public service provision. In reality, this often means jumping from state monopoly to private oligopoly, with public service markets dominated by large outsourcing companies, many with a record of shoddy service. Chris PainterEmeritus professor, Birmingham City University

• By private sector efficiency, does Mr Herbert mean the gas, electricity and water companies? Think of their prices. Or the entrepreneurial spirit of G4S charging to tag people who have died? Or Serco's cost-cutting in out of hours services? The banks? G4S at the Olympics? Best not go there. The NHS? No, the NHS is one of the most cost-efficient health services in the developed world. Care costs in the largely private US health system are about twice the NHS's. And why have I time to write this letter? Because my privatised train is running two hours late. Peter NicklinNewcastle upon Tyne

• "Britain spends proportionately far less on private healthcare than other developed countries," Nick Herbert says. Er, that's the point of a national health service funded from general taxation, Nick. Perhaps you could write an article explaining why it's bad that we don't have to spend a fortune if we fall ill.George BennRomsey, Hampshire

• Nick Herbert's smoothing piece on police efficiency should remind us that we continue to be softened up for privatisation in essential services. We know that good leadership and good management are found in the private and public sectors; good practice can be exchanged and shared to the benefit of both. Evidence of the inherent superiority of profit-centred management seems hard to come by. The lesson for the public sector is: sharpen your pencils and re-invent the principles of public service before it's too late. Howard LayfieldPonteland, Northumberland

• Nick Herbert suggests that we all used to measure the quality of services by how expensive they were. In Westminster they may have done, but the rest of us judge them on their quality.John PawseyMilton Keynes

• Could I ask that when MPs, of whatever party, are given space on the Comment page, this is followed by a summary of their register of interests? It would be have been enlightening to read of Nick Herbert's connections with Chime Communications plc (Report, 12 July 2008), which does excellent work on behalf of its healthcare clients.Dr Ian GroundHeaton, Newcastle

• Alarm bells should be ringing at the news of a £1.1bn contract to outsource healthcare (Report, 27 July). Ministers may welcome providers who offer services at the lowest price but such a benefit is likely to be short-lived. The BMA is already expressing concern that large non-NHS providers could have an advantage over smaller competitors in the tender process. The "free" market is good at letting the strong get stronger and the weak go to the wall. Such was the outcome in banking, and the energy industry has finished up with half a dozen firms that hardly compete vigorously. In 10 years the balance of power will have moved away from the NHS to near-monopoly private suppliers. Roger HeapeWinchester, Hampshire

• When outsourcing public services the rule is not that you get what you pay for, but that you pay and get what is in the contract. It is nigh on impossible for an under-resourced public sector organisation to describe its requirements in every last detail or to define a comprehensive and ungameable performance measurement mechanism. Given that when it comes to the crunch, neither the purchaser nor its masters in central government will have the guts to terminate a faltering contract, and that the use of past performance as a selection criterion is constrained by EU regulations, it's no wonder Big Outsource is laughing all the way to the bank.David MarcerMaisemore, Gloucester